RE: [APML] Another intro

["Jason Lewis" <jlewis@nomoon.org>]

I thought that a secondary with a higher magnification would
produce more field curvature.  I would also think that the
higher secondary magnification would also make the OTA more
susceptible to thermal expansion problems.  Also, wouldn't an
OTA with a larger primary with the same OTA f/ratio produce a
flatter field?    Can someone confirm this?  On the other
hand, I have heard nothing but good things about the  C9.25.

Jason

-----Original Message-----
I recall reading somewhere that the C9.25 has an f/3.3 primary
and the
secondary magnification is about 3, whereas the "normal" SCTs
have an f/2
primary and a secondary magnification of 5.  I may have the
specific numbers
wrong, but the C9.25 supposedly has a slower primary.  That
could be the
reason for the flatter field.


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